On Jan. 9, 1943, as World War II raged, President Franklin Roosevelt left Washington on a train heading north. It was a misdirection meant to trick journalists into thinking Roosevelt was headed to his estate in upstate New York, Paul M. Sparrow, director of the FDR Presidential Library recounts. It worked.

In Baltimore, Roosevelt covertly switched to a train bound for Miami. From there, he boarded a plane headed south, becoming the first president to fly in an airplane while in office.

What followed was an itinerary that would intimidate even a modern, young jetsetter: a 10-hour flight to Trinidad and Tobago; a nine-hour flight to Para River, Brazil; a 19-hour flight over the Atlantic to Gambia, and an 11-hour flight to Casablanca in what is now Morocco. Roosevelt arrived at his final destination on the evening of Jan. 14 - five days after he left the White House.

On Wednesday, President Donald Trump made his first visit to troops in a conflict zone, flying to Al Asad Air Base near Baghdad after months of public pressure. In doing so, Trump was following in the footsteps of other commanders in chief, from James Madison and Abraham Lincoln to FDR.

Admittedly, visiting U.S. troops fighting in North Africa was not the main purpose of Roosevelt's trip overseas. He went to Casablanca to strategize in secret with British prime minister Winston Churchill, French commander Charles de Gaulle, and their military leaders. But at the close of the meetings, and against Secret Service recommendations, Roosevelt decided to meet with some of the men he commanded.

A few journalists were brought in to cover the occasion (though they weren't allowed to report it until days later when Roosevelt was well into the long trip home). At the first stop, United Press correspondent Walter Logan said, soldiers stood at attention for a "review," expecting only high-ranking officers to inspect them. As a jeep carrying the president slowly passed by, the surprise of his presence left "their faces wreathed in smiles."

They stopped at a field kitchen for lunch, where Roosevelt dined on the same rations as everyone else: ham, green beans and sweet potatoes. There, "he was introduced to fifty representative men and officers who were decorated with Silver Stars and Purple Hearts," Logan said.

Roosevelt and his convoy drove to visit several more companies throughout the afternoon, before ending the day at a fresh military cemetery near the town of Mehdia.

"Roosevelt was deeply moved by the experience and when he returned home he wrote dozens of personal letters to the families of servicemen he met and to the families of the soldiers buried at Mehdia," Sparrow says.

Riding alongside Roosevelt for much of the tour was Dwight Eisenhower, who was then the Allied commander in the North African theater. Years later, when Eisenhower was running for president, he promised to continue the precedent by visiting U.S. troops fighting in Korea. He did so months later as president-elect.

During the Vietnam War, both Lyndon Johnson and Richard Nixon visited the troops fighting there.

And in more recent history, former presidents George H.W. Bush, Bill Clinton, George W. Bush and Barack Obama all visited troops in combat zones. Now Trump has added to that history and tradition.